Integration / Apache Pulsar Interview questions
How does namespace bundle splitting work?
A namespace's set of topics is divided into fixed hash-range slices called bundles, which are the actual unit of load assignment - brokers own bundles, not individual topics directly, keeping ownership bookkeeping manageable even with millions of topics.
When a bundle grows too hot (too much throughput or too many topics concentrated in one hash range), the load manager can split it into two smaller bundles, each covering half the original hash range, which can then be assigned to different brokers.
This split happens without moving message data - it only changes how topic ownership is partitioned and assigned - so it's a lightweight rebalancing operation compared to physically relocating stored data.
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